Metabolic profiling of probiotic strain Lactobacillus delbrueckii subsp. bulgaricus L14 cultivated in presence of prebiotic oligosaccharides and polysaccharides in simulating in vitro gastrointestinal tract system

Figures & data

Figure 1. Scheme of simulated gastrointestinal digestion model involving simulated gastric fluid and simulated intestinal fluid and performed analysis.

Figure 2. Degree of the hydrolysis of studied prebiotic oligosaccharides and polysaccharides in conditions simulating gastric fluid after period of 2 h (1% lactulose (A), 1% GalOS (B), 1% FOS (C), 1% inulin (D), and 1% β-glucan (E)).

Table 1. Residual oligosaccharide concentrations and percent of their hydrolysis obtained after 1% lactulose, GalOS and FOS fermentation in conditions simulating SIF in the presence of Lb. delbrueckii subsp. bulgaricus L14.*

	Residual concentration (mg/mL)		Hydrolysis (%)
	0 h	4 h
Lactulose	11.04 ± 0.25	7.27 ± 0.5	34.15
GalOS with DP ≥ 4	5.95 ± 0.21	1.63 ± 0.34	72.6
FOS1 DP 4	7.6 ± 0.18	7 ± 0.28	8
FOS2 DP 6	6.3 ± 0.18	5.2 ± 0.48	18

*Values are means of three measurements ± SD.

Table 2. Residual monosaccharide concentrations obtained after 1% lactulose, GalOS and FOS fermentation in conditions simulating SIF in the presence of Lb. delbrueckii subsp. bulgaricus L14.*.

Time (h)	1% Lactulose	1% GalOS	1% FOS
	Fructose (mg/mL)	Galactose (mg/mL)	Fructose (mg/mL)
0	0.67 ± 0.2	6.76 ± 0.5	0.8 ± 0.11
1	0.57 ± 0.21	6.15 ± 0.34	0.8 ± 0.09
2	0.6 ± 0.18	7.48 ± 0.28	0.7 ± 0.15
3	0	7.64 ± 0.18	0.6 ± 0.2
4	0	7.87 ± 0.32	0.6 ± 0.1

*Values are means of three measurements ± SD.

Table 3. Residual monosaccharide and oligosaccharide concentrations obtained after 1% inulin and β-glucan fermentation in conditions simulating SIF in the presence of Lb. delbrueckii subsp. bulgaricus L14.*

Time (h)	1% Inulin		1% β-Glucan
	Fructose (mg/mL)	Kestose (mg/mL)	Glucose (mg/mL)	DP2 (mg/mL)
0	3.38 ± 0.21	2.8 ± 0.14	2.7 ± 0.48	2.2 ± 0.21
4	5.6 ± 0.15	1.95 ± 0.17	3.8 ± 0.35	3.3 ± 0.28

*Values are means of three measurements ± SD.

Figure 3. Dynamics of cell growth of Lb. delbrueckii subsp. bulgaricus L14 strain, in the presence of different oligosaccharides in conditions simulating the small intestine fluid.

*Values are means of three measurements ± SD.

Table 4. Dynamics of changes in the specific activity of the enzymes from Lb. delbrueckii subsp. bulgaricus L14 in the presence of different oligosaccharides in conditions simulating the SIF.*

	Time (h)	α-Galactosidase (U/mg protein)	β-Galactosidase (U/mg protein)	α-Glucosidase (U/mg protein)	β-Glucosidase (U/mg protein)	Inulinase (U/mg protein)
1% Lactulose	2	0	0.46 ± 0.05	0.03 ± 0.01	n/a	n/a
	3	0.04 ± 0.009	0.45 ± 0.08	0	n/a	n/a
	4	0	0	0	n/a	n/a
1% GalOS	2	0.02 ± 0.008	0.04 ± 0.01	0.14 ± 0.07	n/a	n/a
	3	0	0.12 ± 0.05	0.2 ± 0.04	n/a	n/a
	4	0	0.13 ± 0.08	0.09 ± 0.01	n/a	n/a
1% FOS	2	n/a	0.1 ± 0.009	0	0	0.05 ± 0.01
	3	n/a	0.04 ± 0.01	0.03 ± 0.007	0.04 ± 0.009	0.2 ± 0.05
	4	n/a	0.05 ± 0.01	0.04 ± 0.006	0	0.13 ± 0.03
1% Inulin	2	n/a	0	0.02 ± 0.001	n/a	0.04 ± 0.005
	3	n/a	0.04 ± 0.008	0.07 ± 0.01	n/a	0.08 ± 0.01
	4	n/a	0.06 ± 0.01	0.04 ± 0.001	n/a	0.11 ± 0.01
1% β-glucan	2	0	n/a	0.04 ± 0.01	0.45 ± 0.1	n/a
	3	0.03 ± 0.009	n/a	0.05 ± 0.01	1.27 ± 0.16	n/a
	4	0	n/a	0.04 ± 0.008	1.33 ± 0.18	n/a
0.5% lactulose + 0.5% β-glucan	2	0.02 ± 0.005	0.28 ± 0.05	n/a	0.03 ± 0.01	n/a
	3	0	5.72 ± 0.7	n/a	0.25 ± 0.05	n/a
	4	0	1.02 ± 0.08	n/a	0.02 ± 0.005	n/a

*Values are means of three measurements ± SD; n/a - not applicable.

Table 5. Organic and short-chain fatty acids concentrations obtained after utilization of different oligosaccharides in conditions simulating SIF in the presence of Lb. delbrueckii subsp. bulgaricus L14.

	Time (h)	D-Lactate (mmol/L)	L-Lactate (mmol/L)	Acetate (mmol/L)	Butyrate (mmol/L)
1% Lactulose	1	17.7 ± 1.68	4.87 ± 0.52	0	0
	2	13.8 ± 1.47	3.78 ± 0.15	1.62 ± 0.09	0
	3	13.39 ± 1.09	4.73 ± 0.39	7.42 ± 0.87	0.6 ± 0.05
	4	17.81 ± 2.42	3.4 ± 0.11	14.93 ± 1.29	0
1% GalOS	1	0	3.14 ± 0.14	9.58 ± 1.02	0
	2	0	3.53 ± 0.11	12.64 ± 0.99	0
	3	40.63 ± 3.54	2.26 ± 0.81	0	0
	4	78.96 ± 4.22	2.56 ± 0.44	0	0
1% FOS	1	25.56 ± 1.88	2.55 ± 0.1	0	1 ± 0.2
	2	31.88 ± 2	3.79 ± 0..25	0	1 ± 0.06
	3	32.29 ± 1.87	2.46 ± 0.19	0	0
	4	22.16 ± 0.79	2.09 ± 0.35	0	0
1% Inulin	1	7 ± 0.54	1.42 ± 0.41	0	0.75 ± 0.12
	2	9.8 ± 0.75	1.88 ± 0.09	0	0
	3	11.46 ± 1.31	2.19 ± 0.14	0	0
	4	19.84 ± 1.9	3.07 ± 0.19	0	0
1% β-glucan	1	12.59 ± 1.02	3.69 ± 0.88	0	0.4 ± 0.03
	2	14.49 ± 1.58	4.85 ± 0.11	0	0
	3	14.5 ± 2.01	4.94 ± 0.78	0	0
	4	0.58 ± 0.12	16.27 ± 3.22	1.5 ± 0.18	0
0.5% lactulose + 0.5% β-glucan	1	12.66 ± 1.44	3.4 ± 0.47	0	0
	2	16.26 ± 1.78	5.14 ± 0.39	0	0
	3	17.2 ± 1.06	4.87 ± 0.59	0	0.56 ± 0.07
	4	20.51 ± 2.32	5.12 ± 0.47	0	0

*Values are means of three measurements ± SD.

Data availability statement

All data that support the findings reported in this study are available from the corresponding author upon reasonable request.